In the past various types of aquatic harvesters or weed cutters have been provided, operating on a principle whereby aquatic plants are mechanically cut at the end of a moving conveyor belt which then carries the plants on board the harvester. Such harvesters have the disadvantage that the harvesting is not selective in that all material above the height of the cutting blades is removed. Such machinery is also of considerable weight, requiring a comparatively deep draught vessel in order to accommodate the machinery in a vessel of manoeuvrable proportions. This is a disadvantage with an aquatic harvester which is frequently required to operate in shallow water as aquatic plants are most prevelant in shallow water due to light penetration.
Some known aquatic harvesters are supported by wheels or tracks which run on the sea bed (or lake bed, etc.) to support the harvester, rather than being supported by a float vessel. Such land based machinery has the disadvantage that it can often cause ecological damage to the sea bed due to the disturbance caused by the wheels or tracks.
It is a further feature of known types of floating harvesters that they are normally powered by devices such as paddle wheels which are inefficient in their use of energy, and more importantly, provide no reference to the bottom of the water body. Drift due to wind and currents makes precise harvesting of an area difficult, if not impossible. Wheeled or tracked harvesting machinery provides good ground reference but causes considerable disturbance to the substrate and damage to the ecology of the aquatic environment.
It is therefore an object of the present invention to provide a suction harvester for aquatic plants and harvesters which will obviate or minimise the foregoing disadvantages in a simple yet effective manner, or which will at least provide the public with a useful choice.